The aforementioned patent applications disclose and claim a pumping system in which a quantity of pressurized product is stored in a storage compartment during a pressurizing stroke and discharged through an outlet orifice during a succeeding intake stroke to maintain a stream or spray issuing from the system. The present invention is directed to the provision of a trigger device which is especially advantageous for actuation of such a pumping system. A pumping system of the type disclosed in the copending applications may also include a novel strainer and a novel vent means in accordance with this invention.